This invention relates to twine knotters for hay or straw baling machines and more particularly to an improved wiper arm for such knotters.
In one conventional baler, the twine knotter includes a rotatably mounted billhook for forming a loop of twine thereabout. On one side of the billhook is a wiper arm which has a pair of finers defining a fork for receiving and guiding twine used to tie a bale. On the other side of the billhook is a knife riveted to the fork for cutting the twine after a loop in the twine has been formed around the billhook. A wiper is formed integrally with the fork of the arm and strips or wipes the loop of twine from around the billhook as the severed end of the twine is held in the billhook jaw.
Proper adjustment of the wiper arm relative to the billhook is critical to the operation of the knotter as the wiper must strip or wipe the twine loop from the billhook to complete the formation of the knot. Wiper arm adjustment is performed initially at the point of manufacture and periodically thereafter when servicing the baler. It is accomplished by modeling or bending the arm in three areas with a special tool. By modeling, the wiper is centered with respect to the heel of the billhook and adjusted so that it just clears the billhook jaw. For this reason, it is desirable that the wiper arm be relatively rigid and unyielding so that proper adjustment can be maintained and yet be sufficiently bendable to permit initial adjustment. Also, in recent years, stronger twines are being used on such balers to tie bales of higher density. Such changes subject the wiper arm to higher forces during operation thus making it more difficult to maintain the arm in proper adjustment, while at the same time, making the arm flexible enough to permit initial adjustment.
Accordingly, it is an object of this invention to provide a knotter with an improved wiper arm having a strong and rigid construction to maintain an accurate adjustment.
Another object of this invention is to provide a knotter with a wiper arm which has a wiper which is easily and accurately adjustable with respect to the billhook of the knotter.